Cigarette smoking is viewed as one of the most preventable causes of death and disability in the United States. If the onset of smoking in the adolescent years could be prevented, the total incidence of smoking among adults would be much reduced. Peer influence is widely believed to be a major cause of adolescent smoking. Peer smoking has been found to be the best predictor of adolescent smoking. However, the manner in which peer influence is transmitted among adolescents is not well understood. This research aims toward a systematic integration and extension of the existing knowledge of the ways in which peers influence adolescent cigarette smoking. The research has three major objectives: 1. To specify in a casual model the pathways by which peers may influence adolescents to begin and/or maintain cigarette smoking. 2. To apply this model to data derived from an adolescent population. This will enable the determination of the relative contribution of the designated pathways of peer influence to cigarette smoking. 3. To determine if the relative contribution of these pathways is similar in subgroups of the population that differ on age, sex or value of peer affiliation.